We're going to hear voices now from Parkland, Fla., where a gunman opened fire this afternoon at Marjory Stoneman Douglas High School. This is a developing story, and we're still gathering details. The school superintendent, Robert Runcie, says this appears to be the worst shooting ever in the county.

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ROBERT RUNCIE: There are numerous fatalities. It's a horrific situation.

SHAPIRO: The Broward Sheriff's Office says at least 17 people have died, and more have been injured. Sheriff Scott Israel also confirmed to the media they have a suspect in custody.

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SCOTT ISRAEL: He's 19 years old. He was born in 1998 in September. He was a former student of Douglas High School. He got expelled for disciplinary reasons. I don't know the specifics.

SHAPIRO: The sheriff says the suspect is named Nikolas Cruz. Caitie Switalski of member station WLRN has been talking with students outside Marjory Stoneman Douglas. She says some of them thought this was another fire drill.

CAITIE SWITALSKI, BYLINE: They actually had a fire drill earlier in the day, and the teacher said, hey, you know, we're just having another fire drill. Everybody walk the way you're supposed to walk. And then, you know, once they got there, they had people running up behind them. One student said his - you know, the person that ran up behind him had a huge hole in his foot, and he was yelling, I'm shot; keep going. And teachers just yelled, keep going.

SHAPIRO: One of the students is a high school senior named Brandon Minoff, and here's how he describes what happened.

BRANDON MINOFF: It was a normal class day in last period. And with five minutes left in class, the fire alarm went off. And then once we got outside and were settled, there was gunshots, so we started evacuating. We made our way outside. And then I was - texted my brother to see if he was OK, and he said that his teacher didn't go outside for the fire alarm, and they got stuck inside the school. That's pretty much all I've heard and seen.

SHAPIRO: Parents gathered in a parking lot, waiting for their children. We reached Caesar Figueroa awaiting his daughter.

CAESAR FIGUEROA: Yeah, my daughter is in 11th grade. Her name is Gabrielle (ph) Figueroa. She was trapped. She was in the closet with her friends. She heard gunshots. She heard a window blow and all the kids running around. And for a half hour, I didn't hear from her at all. So I found this out when she texted me after - about, like, probably 20, 30 minutes later - after. And I saw cops coming like crazy with machine guns and helicopters flying. The FBI is here.

SHAPIRO: We also spoke earlier with a parent named Alison Carew. Her twin daughters go to Marjory Stoneman Douglas.

ALISON CAREW: I was actually sitting at my desk at work. I work in Boca, and they both started texting me independently. They were in different classes. One of them said that she was on lockdown in the auditorium, and one was on lockdown in the front office. And they were both scared and telling me that they love me. And I think that's my daughter actually calling me right now.

SHAPIRO: We've learned that both her daughters are safe. Parkland Mayor Christine Hunschofsky described the school for us earlier.

CHRISTINE HUNSCHOFSKY: It's a large school. The schools here in Florida are countywide schools, so this school falls under the Broward County schools. There are over 3,000 students at the school. It's in a very - we're in a very nice, close-knit community. It's a very safe area.

SHAPIRO: Congressman Ted Deutch represents the area, and he, too, says he's shocked a shooting would happen at this high school. He spoke with us from Capitol Hill.

TED DEUTCH: I mean, I can tell you we're going to have a moment of silence in the House, I suppose. And my colleagues have been terrific about reaching out and offering condolences. But nobody should have to go through this ever. And it happens time and time and time again. And if there is anything we can do to prevent one of these from happening in your community, then, by God, we have to.

SHAPIRO: We'll continue to update this story throughout the evening as more details emerge. Transcript provided by NPR, Copyright NPR.